Anti-reflective film

ABSTRACT

Disclosed herein is an anti-reflective film including: a hard coating layer; and a low-refractive layer containing a binder resin, and hollow inorganic nanoparticles and solid inorganic nanoparticles which are dispersed in the binder resin, wherein the low-refractive layer includes a first layer containing at least 70 vol % of the entire solid inorganic nanoparticles and a second layer containing at least 70 vol % of the entire hollow inorganic nanoparticles, and at the time of fitting polarization ellipticity measured by ellipsometry for the first layer or/and the second layer included in the low-refractive layer using a Cauchy model represented by the following General Equation 1, the second layer satisfies a predetermined condition.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/554,966, filed Aug. 31, 2017, which is a National Stage Entry ofInternational Application No. PCT/KR2017/002582, filed Mar. 9, 2017, andclaims the benefit of and priority to Korean Patent Application No.10-2016-0028468 filed on Mar. 9, 2016, Korean Patent Application No.10-2016-0029336 filed on Mar. 11, 2016, Korean Patent Application No.10-2016-0030395 filed on Mar. 14, 2016, and Korean Patent ApplicationNo. 10-2017-0029953 filed on Mar. 9, 2017, the disclosures of which areincorporated by reference in their entireties for all purposes as iffully set forth herein.

FIELD OF THE INVENTION

The present invention relates to an anti-reflective film. Moreparticularly, the present invention relates to an anti-reflective filmcapable of having low reflectance and high light transmittance,simultaneously implementing scratch-resistance and an anti-pollutionproperty, and enhancing sharpness of a screen of a display device.

BACKGROUND OF THE INVENTION

In general, an anti-reflective film is mounted on a flat-panel displaydevice such as a plasma display panel (PDP), a liquid crystal display(LCD), and the like, in order to minimize reflection of incident lightfrom the outside.

As a method for minimizing reflection of light, there are a method ofdispersing fillers such as inorganic fine particles in a resin andcoating the resin on a substrate film to impart unevenness (i.e. ananti-glare (AG) coating method), a method of forming a plurality oflayers having different refractive indices on a substrate film to uselight interference (i.e. an anti-reflection (AR) coating method), acombination of these methods, and the like.

Among them, in the case of the AG coating method, an absolute amount ofreflected light is equivalent to that in a general hard coating method,but it is possible to obtain a low-reflection effect by decreasing anamount of light entering the eyes using scattering of the light throughunevenness. However, since in the AG coating method, sharpness of ascreen is deteriorated due to surface unevenness, recently, the ARcoating method has been variously studied.

As a film using the AR coating method, a film having a multilayerstructure in which a hard coating layer (a high-refractive index layer),a low-reflective coating layer, and the like are laminated on asubstrate film has been commercialized. However, in the method offorming a plurality of layers as described above, since a process offorming each of the layers is separately performed, close interlayeradhesion (interfacial adhesion) may be weak, such that scratchresistance may be deteriorated.

Further, in order to improve scratch resistance of the low-refractivelayer included in the anti-reflective film, a method of adding variousparticles with a nanometer size (for example, silica particles, aluminaparticles, zeolite particles, or the like) was mainly conducted in thepast. However, in the case of using the particles with a nanometer size,it was difficult to increase scratch resistance while decreasingreflectance of the low-refractive layer, and an anti-pollution propertyof a surface of the low-refractive layer was significantly deteriorateddue to the nanometer-sized particles.

Therefore, various studies for decreasing an absolute reflection amountof light incident from the outside and improving an anti-pollutionproperty together with scratch resistance of a surface have beenconducted, but physical properties of the anti-reflective film are notsufficiently improved in spite of these studies.

SUMMARY OF THE INVENTION Technical Problem

It is an object of the present invention to provide an anti-reflectivefilm having advantages of having low reflectance and high lighttransmittance, while simultaneously implementing scratch-resistance andan anti-pollution property, and enhancing sharpness of a screen of adisplay device.

Technical Solution

There is provided an anti-reflective film including: a hard coatinglayer; and a low-refractive layer containing a binder resin, and hollowinorganic nanoparticles and solid inorganic nanoparticles which aredispersed in the binder resin,

wherein the low-refractive layer includes a first layer containing atleast 70 vol % of the total volume of solid inorganic nanoparticles anda second layer containing at least 70 vol % of the total volume ofhollow inorganic nanoparticles,

and at the time of fitting polarization ellipticity measured byellipsometry for the second layer included in the low-refractive layerusing a Cauchy model represented by the following General Equation 1,the second layer satisfies the following conditions: A is 1.0 to 1.50, Bis 0 to 0.007, and C is 0 to 1*10⁻³.

$\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In General Equation 1, n(λ) is a refractive index at a wavelength of λ,λ is in a range of 300 nm to 1800 nm, and A, B, and C are Cauchyparameters.

There is also provided an anti-reflective film including: a hard coatinglayer; and a low-refractive layer containing a binder resin, and hollowinorganic nanoparticles and solid inorganic nanoparticles which aredispersed in the binder resin,

wherein the low-refractive layer includes a first layer containing atleast 70 vol % of the total volume of solid inorganic nanoparticles anda second layer containing at least 70 vol % of the total volume ofhollow inorganic nanoparticles,

and at the time of fitting polarization ellipticity measured byellipsometry for the first layer included in the low-refractive layerusing a Cauchy model represented by the following General Equation 1,the first layer satisfies the following conditions: A is 1.0 to 1.65.

$\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In General Equation 1, n(λ) is a refractive index at a wavelength of λ,λ is in a range of 300 nm to 1800 nm, and A, B, and C are Cauchyparameters.

In addition, There is also provided an anti-reflective film including: ahard coating layer; and a low-refractive layer containing a binderresin, and hollow inorganic nanoparticles and solid inorganicnanoparticles which are dispersed in the binder resin,

wherein the low-refractive layer includes a first layer containing atleast 70 vol % of the total volume of solid inorganic nanoparticles anda second layer containing at least 70 vol % of the total volume ofhollow inorganic nanoparticles,

and at the time of fitting polarization ellipticity measured byellipsometry for the first layer and the second layer included in thelow-refractive layer using a Cauchy model represented by the followingGeneral Equation 1, the difference between the A value for the firstlayer and the A value for the second layer is 0.100 to 0.200.

$\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In General Equation 1, n(λ) is a refractive index at a wavelength of λ,λ is in a range of 300 nm to 1800 nm, and A, B, and C are Cauchyparameters.

Hereinafter, the anti-reflective film according to exemplary embodimentsof the present invention will be described in more detail.

As used herein, the term “photopolymerizable compound” collectivelyrefers to compounds causing a polymerization reaction when light, forexample, visible light or UV light, is irradiated thereto.

Further, the term “fluorine-containing compound” refers to a compound inwhich at least one fluorine element is contained.

In addition, the term “(meth)acryl” is used as a concept including bothacryl and methacryl.

In addition, the term “(co)polymer” is used as a concept including botha co-polymer and a homo-polymer.

Further, the term “hollow silica particles” means silica particlesderived from a silicon compound or an organic silicon compound in ashape in which an empty space is present on surfaces and/or insides ofsilica particles.

According to the exemplary embodiment of the present invention, there isprovided an anti-reflective film including: a hard coating layer; and alow-refractive layer containing a binder resin, and hollow inorganicnanoparticles and solid inorganic nanoparticles which are dispersed inthe binder resin, wherein the low-refractive layer includes a firstlayer containing at least 70 vol % of the total volume of solidinorganic nanoparticles and a second layer containing at least 70 vol %of the total volume of hollow inorganic nanoparticles, and at the timeof fitting polarization ellipticity measured by ellipsometry for thesecond layer included in the low-refractive layer using the Cauchy modelrepresented by the following General Equation 1, the second layersatisfies the following conditions: A is 1.0 to 1.50, B is 0 to 0.007,and C is 0 to 1*10⁻³.

In the past, in order to increase scratch resistance of ananti-reflective film, an excess amount of inorganic particles was added,but there was a limitation in increasing the scratch resistance of theanti-reflective film, and reflectance and an anti-pollution propertywere rather deteriorated.

Therefore, the present inventors conducted research into ananti-reflective film and confirmed through experiments that in the caseof distributing hollow inorganic nanoparticles and solid inorganicnanoparticles so as to be distinguished from each other in alow-refractive layer included in the anti-reflective film, theanti-reflective film may have low reflectance and high lighttransmittance and simultaneously implement high scratch resistance andanti-pollution properties, thereby completing the present invention.

More specifically, the anti-reflective film may include: the hardcoating layer; and the low-refractive layer containing the binder resin,and the hollow inorganic nanoparticles and solid inorganic nanoparticleswhich are dispersed in the binder resin, wherein the low-refractivelayer includes the first layer containing at least 70 vol % of the totalvolume of solid inorganic nanoparticles and the second layer containingat least 70 vol % of the total volume of hollow inorganic nanoparticles.

At the time of measuring the polarization ellipticity using ellipsometryand fitting the measured data by the Cauchy model, the low-refractivelayer including the first layer containing at least 70 vol % of thetotal volume of solid inorganic nanoparticles and the second layercontaining at least 70 vol % of the total volume of hollow inorganicnanoparticles may exhibit unique Cauchy parameter values.

In detail, at the time of fitting the polarization ellipticity measuredby ellipsometry for the second layer included in the low-refractivelayer using the Cauchy model represented by the following GeneralEquation 1, the second layer may satisfy the following conditions: A is1.0 to 1.50, B is 0 to 0.007, and C is 0 to 1*10⁻³.

In addition, at the time of fitting the polarization ellipticitymeasured by ellipsometry for the second layer included in thelow-refractive layer using the Cauchy model represented by the followingGeneral Equation 1, the second layer may satisfy the followingconditions: A is 1.10 to 1.40, 1.20 to 1.35, or 1.211 to 1.349, B is 0to 0.007, 0 to 0.00550, or 0 to 0.00513, and C is 0 to 1*10⁻³, 0 to5.0*10⁻⁴, or 0 to 4.8685*10⁻⁴.

$\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In General Equation 1, n(λ) is a refractive index at a wavelength of λ,λ is in a range of 300 nm to 1800 nm, and A, B, and C are Cauchyparameters.

In detail, at the time of fitting the polarization ellipticity measuredby ellipsometry for the first layer included in the low-refractive layerusing the Cauchy model represented by General Equation 1, the firstlayer satisfies the following conditions: A is 1.0 to 1.65, B is 0.0010to 0.0350, and C is 0 to 1*10⁻³.

In addition, at the time of fitting the polarization ellipticitymeasured by ellipsometry for the first layer included in thelow-refractive layer using the Cauchy model represented by GeneralEquation 1, the first layer satisfies the following conditions: A is1.30 to 1.55, 1.40 to 1.52, or 1.491 to 1.511, B is 0 to 0.005, 0 to0.00580, or 0 to 0.00573, and C is 0 to 1*10⁻³, 0 to 5.010⁻⁴, or 0 to4.1352*10⁻⁴.

The polarization ellipticity measured by ellipsometry and related data(ellipsometry data (ψ, Δ)) may be measured by a method and an apparatusgenerally known in the art. For example, linear polarization of thefirst and second layers included in the low-refractive layer may bemeasured in a wavelength range of 380 nm to 1000 nm at an incident angleof 70° using an ellipsometer (J. A. Woollam Co. M-2000). The measuredlinear polarization data (ellipsometry data (ψ, Δ)) may be separatelyapplied to the first and second layers using Complete EASE software tothereby be fitted by the Cauchy model represented by General Equation 1so that a mean-squared error (MSE) is 3 or less.

The Cauchy parameters A, B, and C in each of the first and second layersincluded in the low-refractive layer described above are associated withchanges in the refractive index and the extinction coefficient dependingon the wavelength, respectively. In the case in which the second layerincluded in the low-refractive layer satisfies ranges of the Cauchyparameters A, B, and C determined in fitting results using the Cauchymodel represented by General Equation 1 described above, the secondlayer may maintain a fitted electron density and reflectancedistribution therein, such that the anti-reflective film may implementlower reflectance and have a relatively stable structure againstscratches or external contamination materials. In detail, the Cauchyparameter A is associated with a minimum refractive index at eachwavelength, and B and C are associated with a decrease degree of therefractive index depending on an increase in the wavelength.

Further, in the case in which each of the first and second layersincluded in the low-refractive layer satisfies ranges of the Cauchyparameters A, B, and C determined in fitting results using the Cauchymodel represented by General Equation 1 described above, theabove-mentioned effect may be further improved and maximized.

According to the other example embodiment of the present invention,there is provided an anti-reflective film including: a hard coatinglayer; and a low-refractive layer containing a binder resin, and hollowinorganic nanoparticles and solid inorganic nanoparticles which aredispersed in the binder resin, wherein the low-refractive layer includesa first layer containing at least 70 vol % of the total volume of solidinorganic nanoparticles and a second layer containing at least 70 vol %of the total volume of hollow inorganic nanoparticles, and at the timeof fitting polarization ellipticity measured by ellipsometry for thefirst layer included in the low-refractive layer using a Cauchy modelrepresented by the following General Equation 1, the first layersatisfies the following conditions: A is 1.0 to 1.65.

$\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In General Equation 1, n(λ) is a refractive index at a wavelength of λ,λ is in a range of 300 nm to 1800 nm, and A, B, and C are Cauchyparameters.

The Cauchy parameter A is associated with a minimum refractive index ateach wavelength. As the Cauchy parameter A for the first layer includedin the low-refractive layer satisfies 1.0 to 1.65, 1.30 to 1.55, 1.40 to1.52, 1.480 to 1.515, or 1.491 to 1.511, the anti-reflective film of theanother example embodiment can maintain an optimized refractive indexdistribution therein, thereby realizing lower reflectance in a requiredwavelength range.

The polarization ellipticity measured by ellipsometry and related data(Ellipsometry data (ψ,Δ)) may be measured by the method stated in theanti-reflective film of the example embodiment of the present inventionabove.

Specifically, the polarization ellipticity measured by ellipsometry canbe determined by measuring linear polarization in a wavelength range of380 nm to 1000 nm at an incident angle of 70°.

According to another example embodiment of the present invention, thereis provided an anti-reflective film including: a hard coating layer; anda low-refractive layer containing a binder resin, and hollow inorganicnanoparticles and solid inorganic nanoparticles which are dispersed inthe binder resin, wherein the low-refractive layer includes a firstlayer containing at least 70 vol % of the total volume of solidinorganic nanoparticles and a second layer containing at least 70 vol %of the total volume of hollow inorganic nanoparticles, and at the timeof fitting polarization ellipticity measured by ellipsometry for thefirst layer and the second layer included in the low-refractive layerusing a Cauchy model represented by the following General Equation 1,the difference between the A value for the first layer and the A valuefor the second layer is 0.100 to 0.200.

$\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In General Equation 1, n(λ) is a refractive index at a wavelength of λ,λ is in a range of 300 nm to 1800 nm, and A, B, and C are Cauchyparameters.

The Cauchy parameter A is associated with a minimum refractive index ateach wavelength. As the difference between the A value for the firstlayer and the A value for the second layer is 0.100 to 0.200, 0.120 to0.190, 0.140 to 0.180, or 0.145 to 0.177, the antireflection film ofthis embodiment can greatly improve the mechanical properties of theouter surface while maintaining an optimized refractive indexdistribution, thereby realizing lower reflectance and having arelatively stable structure against scratches or external contaminants.

Specifically, at the time of fitting the polarization ellipticitymeasured by ellipsometry for the first layer included in thelow-refractive layer using the Cauchy model represented by GeneralEquation 1, the first layer satisfies the following conditions: A may be1.0 to 1.65, 1.30 to 1.55, 1.40 to 1.52, or 1.491 to 1.511.

In addition, at the time of fitting the polarization ellipticitymeasured by ellipsometry for the second layer included in thelow-refractive layer using the Cauchy model represented by the followingGeneral Equation 1, the second layer may satisfy the followingconditions: A may be 1.0 to 1.50, 1.10 to 1.40, 1.20 to 1.35, or 1.211to 1.349.

The polarization ellipticity measured by ellipsometry and related data(ellipsometry data (ψ,Δ)) may be measured by the method stated in theanti-reflective film of the example embodiment of the present inventionabove.

Specifically, the polarization ellipticity measured by ellipsometry canbe determined by measuring linear polarization in a wavelength range of380 nm to 1000 nm at an incident angle of 70°.

Hereinafter, the specific contents of the antireflection film of theabove embodiment(s) will be described.

Meanwhile, in the anti-reflective film according to the exemplaryembodiment, the low-refractive layer may include a first layercontaining at least 70 vol % of the total volume of solid inorganicnanoparticles and a second layer containing at least 70 vol % of thetotal volume of hollow inorganic nanoparticles, wherein the first layermay be positioned to be closer to the interface between the hard coatinglayer and the low-refractive layer than the second layer.

In the low-refractive layer of the anti-reflective film, the solidinorganic nanoparticles are mainly distributed in a region close to theinterface between the hard coating layer and the low-refractive layer,and the hollow inorganic nanoparticles are mainly distributed in aregion opposite to the interface, wherein the regions in which the solidinorganic nanoparticles and the hollow inorganic nanoparticles aremainly distributed, respectively, may form individual layers which maybe visibly confirmed in the low-refractive layer.

More specifically, in the case of mainly distributing the solidinorganic nanoparticles in the region of the low-refractive layer of theanti-reflective film close to the interface between the hard coatinglayer and the low-refractive layer and mainly distributing the hollowinorganic nanoparticles in the region of the low-refractive layeropposite to the interface, it is possible to achieve lower reflectancethan an actual reflectance which could be obtained using the inorganicparticles in the past, and the low-refractive layer may simultaneouslyimplement significantly improved scratch resistance and anti-pollutionproperties.

In addition, the first layer containing at least 70 vol % of the totalvolume of solid inorganic nanoparticles may be located within 50% of thetotal thickness of the low-refractive layer from the interface betweenthe hard coating layer and the low-refractive layer.

More specifically, the first layer containing at least 70 vol % of thetotal volume of solid inorganic nanoparticles may be located within 30%of the total thickness of the low refractive layer from the interfacebetween the hard coating layer and the low-refractive layer.

Further, as described above, the hollow inorganic nanoparticles may bemainly distributed in the region of the low-refractive layer opposite tothe interface between the hard coating layer and low-refractive layer.In detail, at least 30 vol % of the total volume of hollow inorganicnanoparticles may be present at a distance farther than that of thetotal volume of solid inorganic nanoparticles from the interface betweenthe hard coating layer and low-refractive layer in a thickness directionof the low-refractive layer. Accordingly, as described above, the firstlayer may be positioned closer to the interface between the hard coatinglayer and the low-refractive layer than the second layer.

As described above, it can be visually confirmed that each of the firstlayer and the second layer, in which the solid inorganic nanoparticlesand the hollow inorganic nanoparticles are mainly distributed,respectively, is present in the low-refractive layer.

For example, it can be visually confirmed that each of the first layerand the second layer is present in the low refractive layer by using atransmission electron microscope or a scanning electron microscope.Further, the ratio of the solid inorganic nanoparticles and the hollowinorganic nanoparticles distributed in the first layer and the secondlayer in the low-refractive layer can also be confirmed.

Meanwhile, each of the first layer containing at least 70 vol % of thetotal volume of solid inorganic nanoparticles and the second layercontaining at least 70 vol % of the total volume of hollow inorganicnanoparticles share a common optical property in one layer, and thus canbe defined as a single layer.

Specifically, at the time of fitting polarization ellipticity measuredby ellipsometry for the first layer and the second layer included in thelow-refractive layer using a Cauchy model represented by the aboveGeneral Equation 1, they have specific Cauchy parameters A, B, and C sothat the first and second layers can be distinguished from each other.

Also, since the thicknesses of the first layer and the second layer canbe derived through fitting the ellipticity of the polarization measuredby the ellipsometry with a Cauchy model represented by the above GeneralEquation 1, the first layer and the second layer in the low refractivelayer can be defined.

Meanwhile, at the time of fitting polarization ellipticity measured byellipsometry using a Cauchy model represented by the above GeneralEquation 1, the Cauchy parameters A, B, and C may be an average value inone layer.

Accordingly, when there is an interface between the first layer and thesecond layer, there may be a region where the first layer and the secondlayer overlap with the Cauchy parameters A, B, and C.

However, even in this case, the thickness and the position of the firstlayer and the second layer can be specified along the region satisfyingthe average value of the Cauchy parameters A, B, and C of each of thefirst layer and the second layer.

“At least 70 vol % of the total volume of solid inorganic nanoparticlesare present in a specific region” means that most of the solid inorganicnanoparticles are present in the specific region in a cross-section ofthe low-refractive layer. In detail, at least 70 vol % of the totalvolume of solid inorganic nanoparticles may be confirmed by measuring atotal volume of the solid inorganic nanoparticles.

Whether or not the hollow inorganic nanoparticles and the solidinorganic nanoparticles are present in specific regions may bedetermined by whether each of the hollow inorganic nanoparticles or eachof the solid inorganic nanoparticles is present in the specific region,except for particles present on an interface of the specific region.

As the solid inorganic nanoparticles are mainly distributed in theregion of the low-refractive layer of the anti-reflective film close tothe interface between the hard coating layer and the low-refractivelayer and the hollow inorganic nanoparticles are mainly distributed inthe region of the low-refractive layer opposite to the interface, two ormore portions or two or more layers having different refractive indicesmay be formed in the low-refractive layer, and thus the reflectance ofthe anti-reflective film may be decreased.

Specific distribution of the solid inorganic nanoparticles and thehollow inorganic nanoparticles in the low-refractive layer may beobtained by adjusting a density difference between the solid inorganicnanoparticles and the hollow inorganic nanoparticles and adjusting adrying temperature of a photocurable resin composition for forming alow-refractive layer, containing the two kinds of nanoparticles asdescribed above, in a specific manufacturing method to be describedbelow.

In detail, a density of the solid inorganic nanoparticles may be atleast 0.50 g/cm³ higher than that of the hollow inorganic nanoparticles,the difference in density between the solid inorganic nanoparticles andthe hollow inorganic nanoparticles may be 0.50 g/cm³ to 1.50 g/cm³, or0.60 g/cm³ to 1.00 g/cm³. Due to this density difference, the solidinorganic nanoparticles may be positioned in the low-refractive layerformed on the hard coating layer to be closer to the hard coating layer.

However, as can be seen from the production method and examplesdescribed later, it is necessary to implement a predetermined dryingtemperature and time to achieve the distribution of particles in the lowrefraction layer in spite of the difference in density between the twokinds of particles

In the case of mainly distributing the solid inorganic nanoparticles inthe region of the low-refractive layer of the anti-reflective film closeto the interface between the hard coating layer and the low-refractivelayer and mainly distributing the hollow inorganic nanoparticles in theregion of the low-refractive layer opposite to the interface, it ispossible to achieve lower reflectance than the actual reflectance whichcould be obtained using the inorganic particles in the past.

In detail, the anti-reflective film may have average reflectance of 1.5%or less, 1.0% or less, 0.50% to 1.0%, 0.60% to 0.70%, or 0.62% to 0.67%in a visible light wavelength region of 380 nm to 780 nm.

Meanwhile, the first layer may have a thickness of 1 nm to 50 nm, 2 nmto 40 nm, or 3 nm to 30 nm, and the second layer may have a thickness of5 nm to 300 nm, 10 nm to 200 nm, from 20 nm to 150 nm, from 25 nm to 120nm, or from 30 nm to 100 nm.

The thicknesses of the first and second layers may also be confirmed byfitting the polarization ellipticity measured by ellipsometry using theCauchy model represented by General Formula 1.

The solid inorganic nanoparticles are particles having a maximumdiameter of 100 nm or less and a shape in which an empty space is notpresent in the insides thereof.

Further, the hollow inorganic nanoparticles are particles having amaximum diameter of 200 nm or less and a shape in which an empty spaceis present on surfaces and/or the insides thereof.

The solid inorganic nanoparticles may have a diameter of 5 to 100 nm, 1to 50 nm, 5 to 30 nm, or 10 to 20 nm.

The hollow inorganic nanoparticles may have a diameter of 1 to 200 nm,10 to 100 nm, 20 to 80 nm, or 40 to 70 nm.

The diameter of the solid inorganic nanoparticles and the hollowinorganic nanoparticles may mean the longest diameter of each ofnanoparticles, which is identified on the cross-section.

Meanwhile, each of the solid inorganic nanoparticles and the hollowinorganic nanoparticles contains one or more reactive functional groupsselected from the group consisting of a (meth)acrylate group, an epoxidegroup, a vinyl group, and a thiol group on a surface thereof.

As each of the solid inorganic nanoparticles and the hollow inorganicnanoparticles contains the above-mentioned reactive functional group onthe surface thereof, the low-refractive layer may have a highercross-linking density, and thus it is possible to secure furtherimproved scratch resistance and anti-pollution properties.

In the antireflection film of the embodiment(s) described above, thefirst layer and the second layer included in the low refractive layermay have refractive indexes in different ranges.

More specifically, the first layer included in the low refraction layermay have a refractive index in a range of 1.420 to 1.600, 1.450 to1.550, 1.480 to 1.520, or 1.491 to 1.511, at 550 nm.

In addition, the second layer included in the low refractive layer mayhave a refractive index in a range of 1.200 to 1.410, 1.210 to 1.400, or1.211 to 1.375, at 550 nm.

The polarization ellipticity measured by ellipsometry and related data(Ellipsometry data (ψ,Δ)) may be measured by a method and an apparatusgenerally known in the art.

The refractive index can be measured by a conventionally known method.For example, the refractive index can be determined by calculating therefractive index at 550 nm based on the elliptically polarized light andthe Cauchy model measured at a wavelength of 380 nm to 1000 nm for eachof the first layer and the second layer included in the low refractivelayer

Meanwhile, the low-refractive layer as described above may bemanufactured from a photocurable coating composition containing aphotopolymerizable compound, a fluorine-containing compound including aphotoreactive functional group, the hollow inorganic nanoparticles, thesolid inorganic nanoparticles, and a photoinitiator.

Therefore, the binder resin contained in the low-refractive layercontains a cross-linked (co)polymer between a (co)polymer of thephotopolymerizable compound and the fluorine-containing compoundincluding the photoreactive functional group.

The photopolymerizable compound contained in the photocurable coatingcomposition according to the exemplary embodiment may form a substrateof the binder resin of the manufactured low-refractive layer. In detail,the photopolymerizable compound may include a monomer or oligomerincluding (meth)acrylate or a vinyl group. In more detail, thephotopolymerizable compound may include a monomer or oligomer includingat least one, at least two, or at least three (meth)acrylates or vinylgroups.

A specific example of the monomer or oligomer including (meth)acrylatemay include: pentaerythritol tri(meth)acrylate, pentaerythritoltetra(meth)acrylate, dipentaerythritol penta(meth)acrylate,dipentaerythritol hexa(meth)acrylate, tripentaerythritolhepta(meth)acrylate, trilene diisocyanate, xylene diisocyanate,hexamethylene diisocyanate, trimethylolpropane tri(meth)acrylate,trimethylolpropane polyethoxy tri(meth)acrylate, trimethylolpropanetrimethacrylate, ethylene glycol dimethacrylate, butanedioldimethacrylate, hexaethyl methacrylate, butyl methacrylate, or a mixtureof two or more thereof; or an urethane modified acrylate oligomer, anepoxide acrylate oligomer, an etheracrylate oligomer, a dendriticacrylate oligomer, or a mixture of two or more thereof. Here, it ispreferable that a molecular weight of the oligomer is 1000 to 10,000.

A specific example of the monomer or oligomer including the vinyl groupmay include divinyl benzene, styrene, or paramethylstyrene.

A content of the photopolymerizable compound in the photocurable coatingcomposition is not particularly limited, but in consideration ofmechanical properties and the like of a low-refractive layer oranti-reflective film to be finally manufactured, the content of thephotopolymerizable compound may be 5 wt % to 80 wt % based on a solidcomponent of the photocurable coating composition. The solid componentof the photocurable coating composition is only a solid-state componentof the photocurable coating composition excluding liquid-statecomponents, for example, an organic solvent and the like, which may beselectively contained as described below.

Meanwhile, the photopolymerizable compound may further contain afluorinated (meth)acrylate-based monomer or oligomer in addition to theabove-mentioned monomer or oligomer. In the case in which thephotopolymerizable compound further contains the fluorinated(meth)acrylate-based monomer or oligomer, a weight ratio of thefluorinated (meth)acrylate-based monomer or oligomer to the monomer oroligomer including the (meth)acrylate or vinyl group may be 0.1% to 10%.

A specific example of the fluorinated (meth)acrylate-based monomer oroligomer may include one or more selected from the group consisting ofcompounds represented by the following Chemical Formulas 11 to 15.

In Chemical Formula 11, R¹ is hydrogen or an alkyl group having 1 to 6carbon atoms, a is an integer of 0 to 7, and b is an integer of 1 to 3.

In Chemical Formula 12, c is an integer of 1 to 10.

In Chemical Formula 13, d is an integer of 1 to 11.

In Chemical Formula 14, e is an integer of 1 to 5.

In Chemical Formula 15, f is an integer of 4 to 10.

Meanwhile, a moiety derived from the fluorine-containing compoundincluding the photoreactive functional group may be contained in thelow-refractive layer.

One or more photoreactive functional groups may be included orsubstituted in the fluorine-containing compound including thephotoreactive functional group, wherein the photoreactive functionalgroup is a functional group capable of participating in a polymerizationreaction by light irradiation, for example, visible light irradiation orUV light irradiation. The photoreactive functional group may includevarious functional groups known to participate in a polymerizationreaction by light irradiation, and a specific example thereof mayinclude a (meth)acrylate group, an epoxide group, a vinyl group, or athiol group.

Each of the fluorine-containing compounds including the photoreactivefunctional group may have a weight average molecular weight (weightaverage molecular weight measured by gel permeation chromatography (GPC)in terms of polystyrene) of 2000 to 200,000, and preferably 5000 to100,000.

When the weight average molecular weight of the fluorine-containingcompounds including the photoreactive functional group is excessivelysmall, the fluorine-containing compounds in the photocurable coatingcomposition may not be uniformly and effectively arranged on a surface,but are positioned inside the finally manufactured low-refractive layersuch that the anti-pollution property of the surface of thelow-refractive layer may be deteriorated, and mechanical properties suchas entire strength, scratch resistance, and the like may be deteriorateddue to a decrease in the cross-linking density of the low-refractivelayer.

Further, when the weight average molecular weight of thefluorine-containing compounds including the photoreactive functionalgroup is excessively large, compatibility with other components in thephotocurable coating composition may be deteriorated, such that a hazeof the finally manufactured low-refractive layer may be increased or thelight transmittance thereof may be decreased, and strength of thelow-refractive layer may also be deteriorated.

In detail, the fluorine-containing compound including the photoreactivefunctional group may be: i) an aliphatic compound or alicyclic compoundin which one or more photoreactive functional groups are substituted,and at least one carbon atom is substituted with one or more fluorineatoms; ii) a heteroaliphatic compound or heteroalicyclic compound inwhich one or more photoreactive functional groups are substituted, atleast one hydrogen atom is substituted with a fluorine atom, and one ormore carbon atoms are substituted with a silicon atom; iii) apolydialkylsiloxane-based polymer (for example, apolydimethylsiloxane-based polymer) in which one or more photoreactivefunctional groups are substituted, and at least one silicon atom issubstituted with one or more fluorine atoms; iv) a polyether compound inwhich one or more photoreactive functional groups are substituted, andat least one hydrogen atom is substituted with a fluorine atom; or amixture of two or more of i) to iv) or a copolymer thereof.

The photocurable coating composition may contain 20 to 300 parts byweight of the fluorine-containing compound including the photoreactivefunctional group, based on 100 parts by weight of the photopolymerizablecompound.

When an amount of the fluorine-containing compound including thephotoreactive functional group is excessively large as compared to thephotopolymerizable compound, a coating property of the photocurablecoating composition according to the exemplary embodiment may bedeteriorated, or the low-refractive layer obtained from the photocurablecoating composition may not have sufficient durability or scratchresistance. Further, when the amount of the fluorine-containing compoundincluding the photoreactive functional group is excessively small ascompared to the photopolymerizable compound, the low-refractive layerobtained from the photocurable coating composition may not havesufficient mechanical properties such as the anti-pollution property,scratch resistance, or the like.

The fluorine-containing compound including the photoreactive functionalgroup may further contain silicon or a silicon compound. That is, thefluorine-containing compound including the photoreactive functionalgroup may selectively contain silicon or the silicon compound therein.More specifically, a content of silicon in the fluorine-containingcompound including the photoreactive functional group may be 0.1 wt % to20 wt %.

The silicon contained in the fluorine-containing compound including thephotoreactive functional group may improve compatibility with othercomponents contained in the photocurable coating composition accordingto the exemplary embodiment, and thus the silicon may serve to increasetransparency by preventing haze generation in the finally manufacturerefractive layer. Meanwhile, when the content of silicon in thefluorine-containing compound including the photoreactive functionalgroup is excessively high, compatibility between other ingredientscontained in the photocurable coating composition and thefluorine-containing compound may be rather deteriorated, and thus thefinally manufactured low-refractive layer or anti-reflective film maynot have sufficient light transmittance or anti-reflection performance,and the anti-pollution property of the surface may also be deteriorated.

The low-refractive layer may contain 10 to 400 parts by weight of thehollow inorganic nanoparticles and 10 to 400 parts by weight of thesolid inorganic nanoparticles, based on 100 parts by weight of the(co)polymer of the photopolymerizable compound.

In the case in which the contents of the hollow inorganic nanoparticlesand the solid inorganic nanoparticles in the low-refractive layer areexcessively high, in a manufacturing process of the low-refractivelayer, the hollow inorganic nanoparticles and the solid inorganicnanoparticles may not be sufficiently phase-separated, but mixedlyexist, such that the reflectance may be increased, and the surface maybecome excessively uneven such that the anti-pollution property may bedeteriorated. Further, in the case in which the contents of the hollowinorganic nanoparticles and the solid inorganic nanoparticles in thelow-refractive layer are excessively low, it may be difficult to allowthe solid inorganic nanoparticles to be mainly positioned in the regionclose to the interface between the hard coating layer and thelow-refractive layer, and the reflectance of the low-refractive layermay be significantly increased.

The low-refractive layer may have a thickness of 1 nm to 300 nm, or 50nm to 200 nm.

Meanwhile, as the hard coating layer, a hard coating layer generallyknown in the art may be used without limitation.

As an example of the hard coating layer, there is a hard coating layercontaining a binder resin containing a photocurable resin, and organicor inorganic fine particles dispersed in the binder resin.

The photocurable resin contained in the hard coating layer, which is apolymer of a photopolymerizable compound capable of causing apolymerization reaction when light such as UV light or the like isirradiated, may be a photocurable resin generally used in the art. Indetail, the photocurable resin may include one or more selected from thegroup consisting of the reactive acrylate oligomer group consisting ofan urethane acrylate oligomer, an epoxide acrylate oligomer, polyesteracrylate, and polyether acrylate; and the multi-functional acrylatemonomer group consisting of dipentaerythritol hexaacrylate,dipentaerythritol hydroxy pentaacrylate, pentaerythritol tetraacrylate,pentaerythritol triacrylate, trimethylene propyl triacrylate,propoxylated glycerol triacrylate, trimethylpropane ethoxy triacrylate,1,6-dihexanediol acrylate, propoxylated glycero triacrylate,tripropylene glycol diacrylate, and ethylene glycol diacrylate.

A particle diameter of the organic or inorganic fine particles is notspecifically limited, but for example, the organic fine particles mayhave a particle diameter of 1 to 10 μm, and the inorganic fine particlesmay have a particle diameter of 1 nm to 500 nm, or 1 nm to 300 nm.

The particle diameter of the organic or inorganic fine particles may bedefined as a volume average particle diameter.

Specific examples of the organic or inorganic fine particles containedin the hard coating layer are not limited, but may include, for example,organic fine particles made of an acrylic resin, a styrene-based resin,an epoxide resin, and a nylon resin, or inorganic fine particles made ofsilicon oxide, titanium dioxide, indium oxide, tin oxide, zirconiumoxide, and zinc oxide.

The binder resin of the hard coating layer further comprises ahigh-molecular weight (co)polymer having weight average molecular weightof 10,000 or more.

The hard coating film may be formed from an anti-glare coatingcomposition containing organic or inorganic fine particles, aphotocurable resin, a photoinitiator, and a high-molecular weight(co)polymer having a weight average molecular weight of 10,000 or more.

Meanwhile, as another example of the hard coating film, there is a hardcoating film containing a binder resin including a photocurable resin,and an antistatic agent dispersed in the binder resin.

The photocurable resin contained in the hard coating layer, which is apolymer of a photopolymerizable compound capable of causing apolymerization reaction when light such as UV light or the like isirradiated, may be a photocurable resin generally used in the art.However, preferably, the photopolymerizable compound may be amulti-functional (meth)acrylate-based monomer or oligomer. Here, in viewof securing physical properties of the hard coating layer, the number of(meth)acrylate-based functional groups is 2 to 10, preferably 2 to 8,and more preferably 2 to 7. More preferably, the photopolymerizablecompound may be one or more selected from the group consisting ofpentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol penta(meth)acrylate, dipentaerythritolhexa(meth)acrylate, dipentaerythritol hepta(meth)acrylate,tripentaerythritol hepta(meth)acrylate, trilene diisocyanate, xylenediisocyanate, hexamethylene diisocyanate, trimethylolpropanetri(meth)acrylate, and trimethylolpropane polyethoxy tri(meth)acrylate.

The antistatic agent may be a quaternary ammonium salt compound; apyridinium salt; a cationic compound having 1 to 3 amino groups; ananionic compound such as a sulfonic acid-based compound, a sulfuric acidester-based compound, a phosphoric acid ester-based compound, aphosphonic acid-based compound, or the like; an amphoteric compound suchas an amino acid-based or amino sulfuric acid ester-based compound, orthe like; a non-ionic compound such as an imino alcohol-based compound,a glycerine-based compound, a polyethylene glycol-based compound, or thelike; an organic metal compound such as metal alkoxide compoundcontaining tin, titanium, etc., or the like; a metal chelate compoundsuch as an acetylacetonate salt of the organic metal compound, or thelike; a reaction product or polymer compound of two or more thereof; ora mixture of two or more thereof. Here, the quaternary ammonium saltcompound may be a compound having one or more quaternary ammonium saltgroups in a molecule, and a low-molecular weight quaternary ammoniumsalt compound or a high-molecular weight quaternary ammonium saltcompound may be used without limitation.

Further, as the antistatic agent, a conductive polymer and metal oxidefine particles may also be used. An example of the conductive polymerincludes aromatic conjugated poly(paraphenylene), heterocyclicconjugated polypyrrole, polythiophene, aliphatic conjugatedpolyacetylene, heteroatom-containing conjugated polyaniline, and a mixedtype of conjugated poly(phenylenevinylene), a double chain conjugatedcompound, which is a conjugated compound having a plurality ofconjugated chains in a molecule, a conductive complex in which aconjugated polymer chain is grafted to or block-copolymerized with asaturated polymer, and the like. Further, the metal oxide fine particlesmay be made of zinc oxide, antimony oxide, tin oxide, cerium oxide,indium tin oxide, indium oxide, aluminum oxide, tin oxide doped withantimony, zinc oxide doped with aluminum, or the like.

The hard coating film containing the binder resin including thephotocurable resin, and the antistatic agent dispersed in the binderresin, may further contain one or more compounds selected from the groupconsisting of an alkoxy silane-based oligomer and a metal alkoxide-basedoligomer.

The alkoxy silane-based compound may be an alkoxy silane-based compoundgenerally used in the art, but may preferably be one or more compoundsselected from the group consisting of tetramethoxysilane,tetraethoxysilane, tetraisopropoxysilane, methyltrimethoxysilane,methyltriethoxysilane, methacryloxypropyltrimethoxysilane,glycidoxypropyl trimethoxysilane, and glycidoxypropyl triethoxysilane.

Further, the metal alkoxide-based oligomer may be prepared by a sol-gelreaction of a composition containing a metal alkoxide-based compound andwater. The sol-gel reaction may be carried out by a method equivalent toa preparation method of the alkoxy silane-based oligomer describedabove.

However, since the metal alkoxide-based compound may violently reactwith water, the sol-gel reaction may be carried out by diluting themetal alkoxide-based compound in an organic solvent and then slowlydripping water thereinto. Here, it is preferable that a molar ratio(based on a metal ions) of the metal alkoxide compound to water isadjusted in a range of 3 to 170 in consideration of reaction efficiency,or the like.

Here, the metal alkoxide-based compound may be one or more compoundsselected from the group consisting of titanium tetra-isopropoxide,zirconium isopropoxide, and aluminum isopropoxide.

The hard coating layer may have a thickness of 0.1 μm to 100 μm.

The anti-reflective film may further include a substrate bonded to theother surface of the hard coating layer. A specific kind or thickness ofthe substrate is not particularly limited, but a substrate known to beused for manufacturing a low-refractive layer or anti-reflective filmmay be used without limitation.

The anti-reflective film according to the exemplary embodiment of thepresent invention may be manufactured by a manufacturing method of ananti-reflective film, including: applying a resin composition forforming a low-refractive layer, containing a photopolymerizable compoundor a (co)polymer thereof, a fluorine-containing compound including aphotoreactive functional group, a photoinitiator, hollow inorganicnanoparticles, and solid inorganic nanoparticles on a hard coating layerand drying the applied resin composition at a temperature of 35° C. to100° C.; and photocuring the dried resin composition.

More specifically, in the anti-reflective film manufactured by themanufacturing method of an anti-reflective film described above, thehollow inorganic nanoparticles and the solid inorganic nanoparticles aredistributed in the low-refractive layer so as to be distinguished fromeach other, such that the anti-reflective film may have low reflectanceand high light transmittance and simultaneously implement high scratchresistance and anti-pollution properties.

In more detail, in the anti-reflective film manufactured by themanufacturing method of an anti-reflective film, the low-refractivelayer may include a first layer containing at least 70 vol % of thetotal volume of solid inorganic nanoparticles and a second layercontaining at least 70 vol % of the total volume of hollow inorganicnanoparticles, wherein the first layer may be positioned to be closer toan interface between the hard coating layer and the low-refractive layerthan the second layer.

The low-refractive layer may be formed by applying the resin compositionfor forming a low-refractive layer, containing the photopolymerizablecompound or the (co)polymer thereof, the fluorine-containing compoundincluding the photoreactive functional group, the photoinitiator, thehollow inorganic nanoparticles, and the solid inorganic nanoparticles onthe hard coating layer, and drying the applied resin composition at atemperature of 35° C. to 100° C. or 40° C. to 80° C.

When a drying temperature of the resin composition for forming alow-refractive layer applied on the hard coating layer is lower than 35°C., an anti-pollution property of the formed low-refractive layer may besignificantly deteriorated. Further, when the drying temperature of theresin composition for forming a low-refractive layer applied on the hardcoating layer is higher than 100° C., in a manufacturing process of thelow-refractive layer, the hollow inorganic nanoparticles and the solidinorganic nanoparticles may not be sufficiently phase-separated, butmixedly exist, such that the scratch resistance and anti-pollutionproperties of the low-refractive layer may be deteriorated, and thereflectance may also be significantly increased.

The low-refractive layer having the above-mentioned characteristics maybe formed by adjusting a density difference between the solid inorganicnanoparticles and the hollow inorganic nanoparticles in addition to thedrying temperature during a drying process of the resin composition forforming a low-refractive layer applied on the hard coating layer. Thedensity of the solid inorganic nanoparticles may be at least 0.50 g/cm³higher than that of the hollow inorganic nanoparticles, and due to thisdensity difference, the solid inorganic nanoparticles may be positionedin the low-refractive layer formed on the hard coating layer to becloser to the hard coating layer.

In detail, the solid inorganic nanoparticles may have a density of 2.00g/cm³ to 4.00 g/cm³ and the hollow inorganic nanoparticles may have adensity of 1.50 g/cm³ to 3.50 g/cm³.

The drying of the resin composition for forming a low-refractive layer,applied on the hard coating layer at a temperature of 35° C. to 100° C.,may be performed for 10 seconds to 5 minutes, or 30 seconds to 4minutes.

When a drying time is excessively short, a phase separation phenomenonbetween the hollow inorganic nanoparticles and the solid inorganicnanoparticles described above may not sufficiently occur. On thecontrary, when the drying time is excessively long, the formedlow-refractive layer may infiltrate into the hard coating layer.

The low-refractive layer may be manufactured from a photocurable coatingcomposition containing a photopolymerizable compound or a (co)polymerthereof, a fluorine-containing compound including a photoreactivefunctional group, the hollow inorganic nanoparticles, the solidinorganic nanoparticles, and a photoinitiator.

The low-refractive layer may be obtained by photocuring the resultantobtained by applying the photocurable coating composition on apredetermined substrate. A specific kind or thickness of the substrateis not particularly limited, but a substrate known to be used formanufacturing a low-refractive layer or anti-reflective film may be usedwithout limitation.

A method and an apparatus generally used to apply the photocurablecoating composition may be used without particular limitation. Forexample, a bar coating method such as a Meyer bar coating method or thelike, a gravure coating method, a 2-roll reverse coating method, avacuum slot die coating method, a 2-roll coating method, or the like,may be used.

The low-refractive layer may have a thickness of 1 nm to 300 nm, or 50nm to 200 nm. Accordingly, the thickness of the photocurable coatingcomposition applied on the predetermined substrate may be about 1 nm to300 nm, or 50 nm to 200 nm.

Accordingly, the thickness of the photocurable coating compositionapplied on the predetermined substrate may be about 1 nm to 300 nm, or50 nm to 200 nm.

In the photocuring of the photocurable coating composition, UV light orvisible light having a wavelength of 200 to 400 nm may be irradiated,and at the time of irradiation, it is preferable that an exposure amountis 100 to 4000 mJ/cm². An exposure time is not particularly limited, butmay be suitably changed depending on a used exposure device, awavelength of the irradiated light, or the exposure amount.

Further, in the photocuring of the photocurable coating composition,nitrogen purging or the like may be performed in order to apply anitrogen atmosphere condition.

Detailed contents of the photopolymerizable compound, the hollowinorganic nanoparticles, the solid inorganic nanoparticles, and thefluorine-containing compound including the photo-reactive functionalgroup include those in the anti-reflective film according to theexemplary embodiment described above.

Each of the hollow inorganic nanoparticles and the solid inorganicnanoparticles may be contained in the composition in a colloidal phasein which they are dispersed in a predetermined dispersion medium. Thecolloidal phase containing each of the hollow inorganic nanoparticlesand the solid inorganic nanoparticles may contain an organic solvent asthe dispersion medium.

A content of the hollow inorganic nanoparticles and a content of thesolid inorganic nanoparticles in the colloidal phase may be determinedin consideration of a content range of the hollow inorganicnanoparticles and a content range of the solid inorganic nanoparticlesin the photocurable coating composition, a viscosity of the photocurablecoating composition, or the like. For example, the solid content of thehollow inorganic nanoparticles and the solid content of the solidinorganic nanoparticles in the colloidal phase may be 5 wt % to 60 wt %,respectively.

An example of the organic solvent used as the dispersion medium mayinclude: alcohols such as methanol, isopropyl alcohol, ethylene glycol,butanol, and the like; ketones such as methylethylketone,methylisobutylketone, and the like; aromatic hydrocarbons such astoluene, xylene, and the like; amides such as dimethylformamide,dimethylacetamide, N-methylpyrrolidone, and the like; esters such asethyl acetate, butyl acetate, gamma-butyrolactone, and the like; etherssuch as tetrahydrofuran, 1,4-dioxane, and the like; or a mixturethereof.

As the photoinitiator, any compound may be used without particularlimitation as long as it is known to be usable in a photocurable resincomposition. More specifically, a benzophenone-based compound, anacetophenone-based compound, a biimidazole-based compound, atriazine-based compound, an oxime-based compound, or a mixture of two ormore thereof may be used.

The photoinitiator may be used in a content of 1 to 100 parts by weightbased on 100 parts by weight of the photopolymerizable compound. Whenthe content of the photoinitiator is excessively low, some materialsthat are not cured in the photocuring of the photocurable coatingcomposition may remain. When the content of the photoinitiator isexcessively high, an unreacted initiator may remain as an impurity or across-linking density may be decreased, such that mechanical propertiesof a manufactured film may be deteriorated, or reflectance thereof maybe significantly increased.

The photocurable coating composition may further contain an organicsolvent.

A non-restrictive example of the organic solvent may include ketones,alcohols, acetates, and ethers, or a mixture of two or more thereof.

A specific example of the organic solvent as described above mayinclude: the ketones such as methylethylketone, methylisobutylketone,acetylacetone, isobutylketone, or the like; the alcohols such asmethanol, ethanol, diacetone alcohol, n-propanol, i-propanol, n-butanol,i-butanol, t-butanol, or the like; the acetates such as ethylacetate,i-propylacetate, polyethylene glycol monomethylether acetate, or thelike; the ethers such as tetrahydrofuran, propylene glycolmonomethylether, or the like; or a mixture of two or more thereof.

The organic solvent may be added at the time of mixing each of thecomponents contained in the photocurable coating composition, or may beadded in a state in which each of the components is dispersed in ormixed with the organic solvent, such that the organic solvent may becontained in the photocurable coating composition. When a content of theorganic solvent in the photocurable coating composition is excessivelylow, flowability of the photocurable coating composition may bedeteriorated, such that defects such as formation of a stripe pattern orthe like may occur in the finally manufactured film. Further, when theorganic solvent is excessively added, a solid content may be decreased,such that coating and film formation may not be sufficiently performed,and thus physical properties or surface characteristics of the film maybe deteriorated, and a defect may occur in the drying and curingprocesses. Therefore, the photocurable coating composition may containthe organic solvent so that a total concentration of the solidcomponents contained therein is 1 wt % to 50 wt %, or 2 wt % to 20 wt %.

A material of the hard coating layer is not particularly limited as longas it is known to be usable in an anti-reflective film.

In detail, the manufacturing method of an anti-reflective film mayfurther include applying a polymer resin composition for forming a hardcoating layer, containing a photopolymerizable compound or a (co)polymerthereof, a photoinitiator, and an antistatic agent on a substrate andphotocuring the applied polymer resin composition, and the hard coatinglayer may be formed by this step.

The components used to form the hard coating layer are the same as thosein the anti-reflective film according to the present invention describedabove.

The polymer resin composition for forming a hard coating layer mayfurther contain one or more compounds selected from the group consistingof an alkoxy silane-based oligomer and a metal alkoxide-based oligomer.

A method and an apparatus generally used to apply the polymer resincomposition for forming a hard coating layer may be used withoutparticular limitation. For example, a bar coating method such as a Meyerbar coating method or the like, a gravure coating method, a 2-rollreverse coating method, a vacuum slot die coating method, a 2-rollcoating method, or the like, may be used.

In the photocuring of the polymer resin composition for forming a hardcoating layer, UV light or visible light having a wavelength of 200 to400 nm may be irradiated, and at the time of irradiation, it ispreferable that an exposure amount is 100 to 4000 mJ/cm². An exposuretime is not particularly limited, but may be suitably changed dependingon a used exposure device, a wavelength of the irradiated light, or theexposure amount. Further, in the photocuring of the polymer resincomposition for forming a hard coating layer, nitrogen purging or thelike may be performed in order to apply a nitrogen atmosphere condition.

Advantageous Effects

According to the present invention, the anti-reflective film capable ofhaving low reflectance and high light transmittance, simultaneouslyimplementing high scratch resistance and anti-pollution properties, andenhancing sharpness of a screen of a display device, and a manufacturingmethod thereof, may be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a transmission electron microscope (TEM) photograph of across-section of an anti-reflective film in Example 1.

FIG. 2 is a TEM photograph of a cross-section of an anti-reflective filmin Example 2.

FIG. 3 is a TEM photograph of a cross-section of an anti-reflective filmin Example 3.

FIG. 4 is a TEM photograph of a cross-section of an anti-reflective filmin Example 4.

FIG. 5 is a TEM photograph of a cross-section of an anti-reflective filmin Example 5.

FIG. 6 is a TEM photograph of a cross-section of an anti-reflective filmin Example 6.

FIG. 7 is a TEM photograph of a cross-section of an anti-reflective filmin Comparative Example 1.

FIG. 8 is a TEM photograph of a cross-section of an anti-reflective filmin Comparative Example 2.

DETAILED DESCRIPTION

The present invention will be described in more detail through thefollowing examples. However, the following examples are only toexemplify the present invention, and contents of the present inventionare not limited by the following examples.

PREPARATION EXAMPLE Preparation Example: Manufacturing of Hard CoatingFilm

A salt-type antistatic hard coating solution (KYOEISHA Chemical Co.,Ltd., solid content: 50 wt %, product name: LJD-1000) was coated on atriacetyl cellulose film using a #10 Mayer bar, dried at 90° C. for 1minute, and irradiated with UV light (150 mJ/cm²), thereby manufacturinga hard coating film having a thickness of about 5 μm.

Examples 1 to 5: Manufacturing of Anti-Reflective Film Examples 1 to 4

(1) Preparation of Photocurable Coating Composition for FormingLow-Refractive Layer

Based on 100 parts by weight of pentaerythritol triacrylate (PETA), 281parts by weight of hollow silica nanoparticles (diameter: about 50 to 60nm, density: 1.96 g/cm³, JGC Catalyst and Chemicals), 63 parts by weightof solid silica nanoparticles (diameter: about 12 nm, density: 2.65g/cm³), 131 parts by weight of a first fluorine-containing compound(X-71-1203M, Shin-Etsu), 19 parts by weight of a secondfluorine-containing compound (RS-537, DIC), and 31 parts by weight of aninitiator (Irgacure 127, Ciba) were diluted in a solvent in which methylisobutyl ketone (MIBK), diacetone alcohol (DAA), and isopropyl alcoholwere mixed at a weight ratio of 3:3:4 so that a solid content was 3 wt%.

(2) Manufacturing of Low-Refractive Layer and Anti-Reflective Film

The photocurable coating composition obtained above was coated on thehard coating film in the preparation example using a #4 Mayer bar so asto have a thickness of about 120 nm, and dried and cured at atemperature illustrated in the following Table 1 for a time illustratedin the following Table 1. At the time of curing, the dried coatingresultant was irradiated with UV light (252 mJ/cm²) under nitrogenpurging.

Example 5

(1) Preparation of Photocurable Coating Composition for FormingLow-Refractive Layer

Based on 100 parts by weight of trimethylolpropane triacrylate (TMPTA),268 parts by weight of hollow silica nanoparticles (diameter: about 50to 60 nm, density: 1.96 g/cm³, JGC Catalyst and Chemicals), 55 parts byweight of solid silica nanoparticles (diameter: about 12 nm, density:2.65 g/cm³), 144 parts by weight of a first fluorine-containing compound(X-71-1203M, Shin-Etsu), 21 parts by weight of a secondfluorine-containing compound (RS-537, DIC), and 31 parts by weight of aninitiator (Irgacure 127, Ciba) were diluted in a methyl isobutyl ketone(MIBK) solvent so that a solid content was 3 wt %.

(2) Manufacturing of Low-Refractive Layer and Anti-Reflective Film

The photocurable coating composition obtained above was coated on thehard coating film in the preparation example using a #4 Mayer bar so asto have a thickness of about 110 to 120 nm, and dried and cured at atemperature illustrated in the following Table 1 for a time illustratedin the following Table 1. At the time of curing, the dried coatingresultant was irradiated with UV light (252 mJ/cm²) under nitrogenpurging.

TABLE 1 Drying Drying Temperature Time Example 1 40° C. 1 min Example 260° C. 1 min Example 3 80° C. 1 min Example 4 60° C. 2 min Example 5 60°C. 3 min

Example 6

(1) Preparation of Hard Coating Later (HD2)

30 g of pentaerythritol triacrylate, 2.5 g of a high molecular weightcopolymer (BEAMSET 371, Arakawa Co. Ltd., Epoxy Acrylate, molecularweight 40,000), 20 g of methylethylketone, and 0.5 g of a leveling agent(Tego wet 270) were uniformly mixed, and then 2 g of an acryl-styrenecopolymer (volume average particle diameter: 2 μm, ManufacturingCompany: Sekisui Plastic) with a refractive index of 1.525 was added asfine particles to prepare a hard coating composition.

The above-obtained hard coating composition was coated on a triacetylcellulose film with a #10 Mayer bar and dried at 90° C. for 1 minute.The dried coating was irradiated by UV at 150 mJ/cm² to prepare a hardcoating layer with a thickness of 5 μm.

(2) Preparation of a Low Refractive Layer and an Anti-Reflective Film

Based on 100 parts by weight of pentaerythritol triacrylate (PETA), 135parts by weight of hollow silica nanoparticles (diameter: about 50 to 60nm, density: 1.96 g/cm³, manufactured by JSC Catalysts and ChemicalsLtd.), 88 parts by weight of solid silica nanoparticles (diameter: about12 nm, density: 2.65 g/cm³), 38 parts by weight of a firstfluorine-containing compound (X-71-1203M, ShinEtsu Chemical Co., Ltd.),11 parts by weight of a second fluorine-containing compound (RS-537,DICCorporation), and 7 parts by weight of an initiator (Irgacure 127, CibaCorporation) were diluted in a mixed solvent of MIBK (methyl isobutylketone):diacetone alcohol (DAA):isopropyl alcohol at a weight ratio of3:3:4 such that the solid concentration became 3 wt %, thus preparing aphotocurable coating composition for forming a low refractive layer.

On the above-prepared hard coating film (HD2), the above obtainedphotocurable coating composition for forming a low refractive layer wascoated to a thickness of about 110 to 120 nm with a #4 Mayer bar, anddried and cured at a temperature of 60° C. for 1 minute. During thecuring, UV at 252 mJ/cm² was irradiated to the dried coating undernitrogen purging.

Comparative Example: Manufacturing of Anti-Reflective Film ComparativeExample 1

An anti-reflective film was manufactured by the same method as inExample 1, except for applying the photocurable coating composition forforming a low-refractive layer and drying the applied photocurablecoating composition at room temperature (25° C.).

Comparative Example 2

A photocurable coating composition for forming a low-refractive layerwas prepared by the same method as in Example 1, except for replacing 63parts by weight of the solid silica nanoparticles used in Example 1 with63 parts by weight of pentaerythritol triacrylate (PETA), and ananti-reflective film was manufactured by the same method as in Example1.

Experimental Example: Measurement of Physical Properties ofAnti-Reflective Film

Experiments composed of the following categories were performed on theanti-reflective films obtained in the examples and comparative examples.

1. Measurement of Average Reflectance of Anti-Reflective Film

Average reflectances of the anti-reflective films obtained in theexamples and comparative examples in a visible light region (380 to 780nm) were measured using Solidspec 3700 (SHIMADZU).

2. Measurement of Anti-Pollution Property

An anti-pollution property was measured by drawing a straight linehaving a length of 5 cm on surfaces of the anti-reflective filmsobtained in the examples and comparative examples using a black name penand confirming the number of scrubbing actions required for erasing thestraight line at the time of scrubbing the antireflective film with awiper.

<Measurement Standard>

◯: The number of rubbing actions required for erasing the straight linewas 10 or less.

Δ: The number of rubbing actions required for erasing the straight linewas 11 to 20.

X: The number of rubbing actions required for erasing the straight linewas more than 20.

3. Measurement of Scratch Resistance

Steel wool was rubbed on surfaces of the anti-reflective films obtainedin the examples and comparative examples under load while reciprocatingthe anti-reflective film at a rate of 27 rpm 10 times. A maximum load atwhich the number of scratches (1 cm or less) observed by the naked eyewas 1 or less was measured.

4. Confirmation of Phase-Separation

When 70 vol % of the entire used solid inorganic nanoparticles (solidsilica nanoparticles) was present within a distance of 30 nm from thehard coating layer in cross-sections of the anti-reflective films inFIGS. 1 to 6, it was determined that phase separation occurred.

5. Ellipsometry Measurement

Polarization ellipticities of the low-refractive layers obtained in theexamples and comparative examples, respectively, were measured usingellipsometry.

In detail, linear polarization of each of the low-refractive layersobtained in the examples and comparative examples was measured in awavelength range of 380 nm to 1000 nm at an incident angle of 70° usingan ellipsometer (J. A. Woollam Co. M-2000). The measured linearpolarization data (ellipsometry data (ψ, Δ)) were fitted for the firstand second layers (Layer 1 and Layer 2) of the low-refractive layerusing Complete EASE software and a Cauchy model represented by thefollowing General Equation 1 so that MSE was 3 or less.

$\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In General Equation 1, n(λ) is a refractive index at a wavelength of λ,λ is in a range of 300 nm to 1800 nm, and A, B, and C are Cauchyparameters.

6. Measurement of Refractive Index

The refractive index at 550 nm was calculated using ellipticallypolarized light and a Cauchy model measured at a wavelength of 380 nm to1000 nm for each of the first layer and the second layer included in thelow refractive index layer obtained in the above examples.

TABLE 2 Comparative Comparative Example 1 Example 2 Example 3 Example 4Example 5 Example 6 Example 1 Example 2 Average 0.63 0.62 0.67 0.64 0.650.67 0.78 0.66 Reflectance (%) Scratch 500 500 500 500 500 500 150 50Resistance(g) Anti-pollution 0 0 0 0 0 0 X X property Phase Separation 00 0 0 0 0 X X Ellipsometry measurment Layer 1 A 1.502 1.505 1.498 1.4911.511 1.505 1.25 1.206 B 0.00351 0.00464 0.00311 0.00573 0.0019240.00316 0.00192 0.07931 C 4.1280*10⁻⁴ 3.4882*10⁻⁴ 4.1352*10⁻⁴3.9821*10⁻⁴ 2.6729*10⁻⁴ 0 0.003 −0.004 Layer 2 A 1.35 1.349 1.321 1.3461.211 1.375 1.33 1.32 B 0.00513 0.00304 0.00312 0 0.00253 0.001780.00786 0.00040374 C 2.5364*10⁻⁴ 0 4.1280*10⁻⁴ 4.8685*10⁻⁴ 1.6421*10⁻⁴1.2131*10⁻⁵ 0.000953 0.000782

TABLE 3 Refractive Exam- Exam- Exam- Exam- Exam- Exam- index ple 1 ple 2ple 3 ple 4 ple 5 ple 6 Layer 1 1.502 1.505 1.498 1.491 1.511 1.505Layer 2 1.35 1.349 1.321 1.346 1.211 1.375

As illustrated in FIGS. 1 to 6, it was confirmed that in thelow-refractive layers of the anti-reflective films in Examples 1 to 6,phase separation between the hollow inorganic nanoparticles and thesolid inorganic nanoparticles occurred.

More specifically, as can be seen from the analysis results of FIGS. 1to 6, it was confirmed that the low-refractive layer included a firstlayer containing at least 70 vol % of the total volume of solidinorganic nanoparticles and a second layer containing at least 70 vol %of the total volume of hollow inorganic nanoparticles, most of the solidinorganic nanoparticles were present and concentrated toward aninterface between the hard coating layer and the low-refractive layer ofthe anti-reflective film, and most of the hollow inorganic nanoparticleswere present and concentrated in a region far from the hard coatinglayer. Accordingly, the first layer containing at least 70% by volume ofthe total solid inorganic nanoparticles is located within 50% of thetotal thickness of the low refractive layer from the interface betweenthe hard coating layer and low-refractive layer.

In addition, at the time of fitting polarization ellipticity measured byellipsometry for the second layer included in the low-refractive layerusing the Cauchy model represented by General Equation 1, the secondlayer satisfied the following conditions: A was 1.0 to 1.50, B was 0 to0.007, and C was 0 to 1*10⁻³. In addition, at the time of fittingpolarization ellipticity measured by ellipsometry for the first layerincluded in the low-refractive layer using the Cauchy model representedby General Equation 1, the first layer satisfied the followingconditions: A was 1.0 to 1.65, B was 0.0010 to 0.0350, and C was 0 to1*10⁻³.

In addition, as illustrated in Table 2, it was confirmed that theanti-reflective films in Examples may have a low reflectance of 0.70% orless in the visible light region and simultaneously implement highscratch resistance and anti-pollution property as illustrated in Table2.

In addition, as shown in Table 3, the first layer and the second layerincluded in the low refraction layer of the examples exhibit differentrefractive indexes. Specifically, it was confirmed that the first layerof the low refraction layer has a refractive index of 1.420 or more andthe second layer of the low refraction layer exhibited a refractiveindex of 1.400 or less.

On the contrary, as illustrated in FIGS. 6 and 7, it was confirmed thatin the low-refractive layers of the anti-reflective films in ComparativeExamples 1 and 2, the hollow inorganic nanoparticles and the solidinorganic nanoparticles were not phase-separated, but mixedly existed.

Further, it was confirmed that in the anti-reflective films inComparative Examples 1 and 2, at the time of fitting the polarizationellipticity measured by ellipsometry using the Cauchy model representedby General Equation 1, measurement results and fitting results by theCauchy model were in a different range from those in the anti-reflectivefilms in Examples, and the anti-reflective films had low scratchresistance and anti-pollution property while having a relatively highreflectance.

What is claimed is:
 1. An anti-reflective film comprising: a hardcoating layer; and a low-refractive index layer, wherein thelow-refractive index layer contains hollow inorganic nanoparticles andsolid inorganic nanoparticles that are dispersed in a binder resin,wherein the low-refractive index layer includes a first layer having arefractive index of 1.420 or more and a second layer having a refractiveindex of 1.400 or less when measured at a wavelength of 550 nm, andwherein the first layer contains at least 70 vol% of the total volume ofthe solid inorganic nanoparticles located within 50% of the totalthickness of the low-refractive index layer from the interface betweenthe hard coating layer and the low-refractive index layer.
 2. Theanti-reflective film according to claim 1, wherein the second layercontains at least 70 vol% of the total volume of hollow inorganicnanoparticles.
 3. The anti-reflective film according to claim 1, whereinthe first layer is positioned closer to an interface between the hardcoating layer and the low-refractive layer than the second layer.
 4. Theanti-reflective film according to claim 1, wherein the second layer haspolarization ellipticity measured by ellipsometry using a Cauchy modelrepresented by the following General Equation 1 in which A is 1.0 to1.50, B is 0 to 0.007, and C is 0 to 1*10⁻³: $\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$ in General Equation 1, n(λ) is a refractive index at awavelength of λ, λ is in a range of 300 nm to 1800 nm, and A, B, and Care Cauchy parameters.
 5. The anti-reflective film according to claim 1,wherein the first layer has polarization ellipticity measured byellipsometry using a Cauchy model represented by the following GeneralEquation 1, in which A is 1.0 to 1.65: $\begin{matrix}{{n(\lambda)} = {A + \frac{B}{\lambda^{2}} + \frac{C}{\lambda^{4}}}} & \left\lbrack {{General}\mspace{14mu}{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$ wherein, in General Equation 1, n(λ) is a refractive indexat a wavelength of λ, λ is in a range of 300 nm to 1800 nm, and A, B,and C are Cauchy parameters.
 6. The anti-reflective film according toclaim 1, wherein the solid inorganic nanoparticles have a density thatis at least 0.50 g/cm³ higher than that of the hollow inorganicnanoparticles.
 7. The anti-reflective film according to claim 1, whereinthe binder resin contained in the low-refractive layer contains across-linked (co)polymer formed from cross-linking a (co)polymer of aphotopolymerizable compound and a fluorine-containing compound includinga photoreactive functional group.
 8. The anti-reflective film accordingto claim 7, wherein the low-refractive layer contains 10 to 400 parts byweight of the hollow inorganic nanoparticles and 10 to 400 parts byweight of the solid inorganic nanoparticles, based on 100 parts byweight of the (co)polymer of the photopolymerizable compound.
 9. Theanti-reflective film according to claim 7, wherein thefluorine-containing compound including the photoreactive functionalgroup has a weight average molecular weight of 2000 to 200,000.
 10. Theanti-reflective film according to claim 7, wherein the binder resincontains 20 to 300 parts by weight of the fluorine-containing compoundincluding the photoreactive functional group based on 100 parts byweight of the (co)polymer of the photopolymerizable compound.
 11. Theanti-reflective film according to claim 1, wherein the hard coatinglayer contains a binder resin containing a photocurable resin, andorganic or inorganic fine particles dispersed in the binder resin. 12.The anti-reflective film according to claim 11, wherein the organic fineparticles have a particle diameter of 1 to 10 μm, and the inorganic fineparticles have a particle diameter of 1 nm to 500 nm.
 13. Theanti-reflective film according to claim 1, wherein the first layerincluded in the low refraction layer has a refractive index in a rangeof 1.420 to 1.600 when measured at a wavelength of 550 nm, and thesecond layer included in the low refractive layer has a refractive indexin a range of 1.200 to 1.410 when measured at a wavelength of 550 nm.14. The anti-reflective film according to claim 1, wherein the hollowinorganic particles are in a higher amount by weight than the solidinorganic particles.
 15. The anti-reflective film according to claim 1,wherein each of the solid inorganic nanoparticles and the hollowinorganic nanoparticles contains one or more reactive functional groupsselected from the group consisting of a (meth)acrylate group, an epoxidegroup, a vinyl group, and a thiol group on a surface thereof.
 16. Theanti-reflective film according to claim 1, wherein the hard coatinglayer contains a binder resin made of a photocurable resin, and anantistatic agent dispersed in the binder resin.
 17. The anti-reflectivefilm of claim 1, having a reflectance of 1.5% or less at a wavelength of380 nm to 780 nm.
 18. The anti-reflective film of claim 1, having areflectance of 0.70% or less at a wavelength of 380 nm to 780 nm. 19.The anti-reflective film of claim 1, wherein the solid inorganicnanoparticles has a diameter of 5 to 100 nm, and the hollow inorganicnanoparticles has a diameter of 1 to 200 nm.